Carburetor, carburetor for mocvd using same, center rod for use in the carburetor or carburetor7 for mocvd, method for dispersing carrier gas, and method for vaporizing carrier gas

ABSTRACT

Provided is a vaporizer that can efficiently cool a carrier gas, improve the effect of preventing a material from being clogged near the outlet port of a gas passage, contribute to prolonging the timing of maintenance and improving operating efficiency, and exert more uniform dispersing effect. A vaporizer includes: a center rod inserted into a carrier gas introduction hole formed in a disperser to form the gas passage in cooperation with the inner wall of the carrier gas introduction hole; a cooling part disposed on the outer circumferential side of the carrier gas introduction hole in the disperser to cool the inside of the gas passage; a cooling member insertion hole formed across almost the entire length of the center rod along the axial direction of the center rod; and a cooling member disposed in the inside of the cooling member insertion hole to cool the center rod.

TECHNICAL FIELD

The present invention relates to a vaporizer for vaporizing a rawmaterial solution or the like made of a plurality of thin film formingmaterials using a carrier gas, a MOCVD vaporizer using the vaporizer, acenter rod for use in the vaporizer or the MOCVD vaporizer, a method fordispersing a carrier gas, and a method for vaporizing a carrier gas.

BACKGROUND ART

In these years, in the field of electronic devices, it is desired tofurther downsize electronic devices and to improve the performance ofelectronic devices as well as to increase the density of circuits. Itbecomes advantageous not only to simply attain the functions ofelectronic devices only by circuitry configurations, like a SRAM (StaticRandom Access read write Memory) and an EEPROM (Electrically Erasableand Programmable Read Only Memory) that perform information storageoperations by combining transistors, or a DRAM (Dynamic Random AccessMemory) or the like that performs information storage operations bycombining a transistor and a capacitor, for example, but also toimplement the functions of devices utilizing the characteristics ofmaterials themselves such as functional thin films.

Furthermore, such semiconductors are mounted for the IC chip of a creditcard or the like, for example, and the technology is being diversifiedinto a personal information memory chip for a passport or the like.

Thus, it is demanded to reduce the thickness of a dielectric material orthe like used for electronic components. There is CVD for a method ofreducing the thickness of such a material.

This CVD has characteristics including a film deposition rate higherthan that of PVD, sol-gel, and other methods, and easy fabrication of amulti-layer thin film. Moreover, MOCVD is CVD using a compoundcontaining an organic substance for a raw material for forming a thinfilm, having such advantages that safety is high and halides are notmixed into films.

Raw materials used for MOCVD are generally solid powder or liquid. Theseraw materials are put in a container, the raw materials are typicallyheated at a subatmospheric pressure and vaporized in a vaporizer, andthen the materials are supplied into a thin film deposition device usinga carrier gas.

FIG. 7 is a system block diagram depicting a vaporization system forsuch MOCVD (see Patent Document 1).

In FIG. 7, 10 denotes a supply unit that supplies a plurality of rawmaterial solutions and the like to a vaporizer 1.

The supply unit 10 includes a gas cylinder 11 filled with a carrier gas(for example, N₂ or Ar), an oxygen cylinder 12 filled with oxygen, awater storage tank 13 having cooling water stored therein, a pluralityof reserve tanks 14 to 17 having raw materials for ferroelectric thinfilms stored therein (for example, sr(DPM)₂, Bi(C₆H₅)₃, and Ta(OC₂H₅)₅)for three kinds of organometallic complexes, and THF (tetrahydrofuran)for a solvent), a gas supply pipe 18 connected to the gas cylinder 11and the vaporizer 1, an oxygen supply pipe 19 connected to the oxygencylinder 12 and the vaporizer 1, a water supply pipe 20 and 6 adistributing pipe 21 connected to the water storage tank 13 and thevaporizer 1, liquid supply pipes 22 to 25 connected to the reserve tanks14 to 17 and the vaporizer 1, and a manifold 26 connected to the reservetanks 14 to 17 and the gas cylinder 11.

A valve 18 a and a mass flow controller 18 b are provided in the path ofthe gas supply pipe 18. A valve 19 a, a mass flow controller 19 b, and avalve 19 c are provided in the path of the oxygen supply pipe 19. Avalve 20 a is provided in the path of the water supply pipe 20.Moreover, a valve 22 a and a mass flow controller 22 b are provided inthe path of the liquid supply pipe 22 for a solvent. Valves 23 a to 25 aand mass flow controllers 23 a to 25 b are provided in the path of theliquid supply pipes 23 to 25 for complexes. Valves 26 a to 26 d, an airpurge 26 e, and a valve 26 f are provided in the path of the manifold26. It is noted that the liquid supply pipes 23 to 25 are branched so asto connect to the liquid supply pipe 22, and provided with valves 23 cto 25 c, respectively.

The valve 18 a of the gas supply pipe 18 is opened to control the flowrate of a carrier gas filled in the gas cylinder 11 by the mass flowcontroller 18 b, and the carrier gas is supplied to the vaporizer 1.Moreover, for the carrier gas filled in the gas cylinder 11, the valve26 f of the manifold 26 and the valves 26 a to 26 d are opened and thereleasing state of the valve 26 e for the air purge is closed, so thatthe carrier gas is supplied to the reserve tanks 14 to 17. Thus, thecarrier gas applies pressure to the insides of the reserve tanks 14 to17, and the stored raw material solutions are each pressed upward in theinsides of the liquid supply pipes 22 to 25 each having the tip endfacing the solution, the flow rates are controlled by the mass flowcontrollers 22 b to 25 b, and then the raw material solutions arecarried to the vaporizer 1.

Furthermore, at the same time, oxygen (an oxidizer) controlled at aconstant flow rate by the mass flow controller 19 b is carried from theoxygen cylinder 12 to the vaporizer 1.

Moreover, the valve 20 a of the water supply pipe 20 is opened tocirculate the cooling water in the water storage tank through the insideof the vaporizer 1 for cooling the vaporizer 1.

It is noted that although the thin film forming material supply parts 27to 30 are arranged side by side along the axial direction of thevaporizer 1 in the example in the drawing, in reality the thin filmforming material supply parts 27 to 30 are radially and alternatelyprovided using connecting parts 31 and 32 connected to the water supplypipe 20 or the distributing pipe 21 from the water storage tank 13.

Since the raw material solutions stored in the insides of the reservetank 15 to 17 have organometallic complexes, (Sr(DPM)₂, Bi(C₆H₅)₃, andTa(OC₂H₅)₅), in liquid or solid solved in THF, a solvent, at roomtemperature, the organometallic complexes are precipitated byevaporating the THF solvent and finally made in a solid if allowed tostand.

Thus, in order to prevent the solid organometallic complexes fromblocking the insides of the liquid supply pipes 23 to 25 contacted tothe undiluted solutions, it is sufficient to clean the insides of theliquid supply pipes 23 to 25 and the inside of the vaporizer 1 afterfilm deposition with THF in the inside of the reserve tank 14. Thecleaning at this time is performed in the section from the outlet portside of the mass flow controllers 13 b to 25 b to the vaporizer 1, usingTHF stored in the inside of the reserve tank 14 after processing.

FIG. 5 is a cross sectional view depicting an exemplary configuration ofthe essential part of the vaporizer 1 (see Patent Document 1).

In the vaporizer 1 shown in FIG. 5, the vaporizer 1 includes a disperser(a dispersing unit main body) 2 to which the gas supply pipe 18 isconnected, a reaction pipe 3 continuously connected to the downstreamside of the disperser 2, and a heater 4 that covers the circumferentialportion of the reaction pipe 3.

The disperser 2 has a gas passage 5 positioned coaxially with the gassupply pipe 18. The tip ends of the thin film forming material supplyparts 27 to 30 are faced between a start upstream port 5 a and an endjet port 5 b of the gas passage 5 (only the thin film forming materialsupply parts 28 and 29 are shown as faced to each other in the drawing),so that the raw material solutions stored in the insides of the reservetank 15 to 17 can be supplied to the inside of the gas passage 5.Moreover, the disperser 2 is formed with a cooling path 6 communicatingwith the connecting parts 31 and 32 for circulating the cooling water inthe inside of the water storage tank 13. Furthermore, the disperser 2includes a center rod 7 having one end positioned at the upstream sidemore than the start upstream port 5 a of the gas supply pipe 18 and theother end positioned at the end jet port 5 b, and a pin 8 that supportsthe tip end side of this center rod 7 (the downstream side of the gaspassage 5). It is noted that the base end side of the center rod 7 (theupstream side of the gas passage 5) is supported by a pin 9 providednear the end portion of the gas supply pipe 18.

In such a configuration, a carrier gas introduction hole is cut throughthe inside of the disperser 2, and the center rod 7 having the outerdiameter (4.48 mm) smaller than the inner diameter (4.50 mm) of thecarrier gas introduction hole is provided so as to be positionedcoaxially with the axis of the carrier gas introduction hole.

Moreover, the gas passage 5 is formed in cooperation with the inner wallof the carrier gas introduction hole and the center rod 7 of thisdisperser 2.

It is noted that the cross sectional width of the gas passage 5 is 0.02mm. At this time, preferably, the cross sectional width of the gaspassage 5 ranges from 0.005 to 0.10 mm. This is because processing isdifficult when the cross sectional width is below 0.005 mm, whereas itis necessary to use a high pressure carrier gas in order to increase therate of the carrier gas when the cross sectional width exceeds 0.10 mm.

A carrier gas is introduced from the gas supply pipe 18 from theupstream of the gas passage 5. Since the raw material solutions aredropped onto this carrier gas from the tip ends of the thin film formingmaterial supply parts 27 to 30 positioned in the midway of the gaspassage 5, these raw material solutions are dispersed into the carriergas passing through the gas passage 5 for mist.

Thus, the carrier gas having the raw material solutions dispersedtherein is issued from the end jet port 5 b on the downstream of the gaspassage 5 to the reaction pipe 3, the carrier gas having the rawmaterial solutions dispersed therein, which flows through the inside ofthe reaction pipe 3, is heated and vaporized with the heater 4, and thenthe carrier gas is supplied to a thin film deposition device, not shownin the drawing.

Now, for the cooling part provided in the vaporizer 1, the cooling path6 is formed across almost the entire length of the gas passage 5 asdescribed above. In addition to this, for example, as shown in FIG. 6,such a configuration is known that a cooling system 33 is provided forcooling the inside of a gas passage 5 positioned in the midway to thetip end side of a center rod 7 (for example, see Patent Document 2).

It is noted that in FIG. 6, functions similar to those of theaforementioned vaporizer 1 shown in FIG. 5 are designated the samereference numerals and signs and the descriptions are omitted.

RELATED ART DOCUMENTS Patent Documents

-   Patent Document 1: JP 2008-001994 A-   Patent Document 2: JP 2004-265938 A

SUMMARY OF THE INVENTION Problems that the Invention is to Solve

Now, in the vaporizer 1 configured as described above, such a phenomenonoccurred that thin film raw materials are attached around the end jetport 5 b of the vaporizer 1.

Namely, since the inside of the gas passage 5 is in a high temperatureenvironment, if moisture in the raw material solutions in mist in thecarrier gas passing through the gas passage 5 (more particularly, thecarrier gas after raw material solutions are dispersed therein) isevaporated before the carrier gas reaches the end jet port 5 b, thepowder components or the like of the materials are attached around theend jet port 5 b. Moreover, such powder components or the like of thematerials grow with time to be a cause to clog the end jet port 5 b aswell as to raise the possibility of developing a problem of mixingimpurities.

Therefore, in order to meet a higher temperature environment in theinside of the gas passage 5, the cooling path 6 is formed on the outercircumferential side than the gas passage 5, and cooling water iscirculated through the cooling path 6 for cooling the gas passage 5.

However, since the cooling path 6 is formed in the disperser 2, aproblem arises in that cooling effect is poor such as the occurrence ofheat loss by the wall thickness of the disperser 2 dividing the gaspassage 5 from the cooling path 6 because the gas passage 5 isindirectly cooled from the outside of the gas passage 5 using heattransfer effect.

In order to solve the aforementioned problems, it is an object of thepresent invention to provide a vaporizer that can efficiently cool acarrier gas, improve the effect of preventing a material from beingclogged near the outlet port of a gas passage, contribute to prolongingthe timing of maintenance and improving operating efficiency, and exertmore uniform dispersing effect.

Means for Solving the Problems

In order to achieve the object, a vaporizer includes: a center rodinserted into a carrier gas introduction hole formed in a dispersingunit main body to form a gas passage in cooperation with an inner wallof the carrier gas introduction hole; a cooling part disposed on anouter circumferential side of the carrier gas introduction hole in thedispersing unit main body and configured to cool an inside of the gaspassage; a cooling member insertion hole formed across almost an entirelength of the center rod along an axial direction of the center rod; anda cooling member disposed in an inside of the cooling member insertionhole and configured to cool the center rod.

It is then possible to efficiently cool a carrier gas using the coolingpart and the cooling member.

Moreover, a vaporizer according to a preferred embodiment, the vaporizerincludes: a center rod inserted across an entire length of a carrier gasintroduction hole formed in a dispersing unit main body to forma gaspassage in cooperation with an inner wall of the carrier gasintroduction hole; a thin film forming material supply part formed at aplurality of places in the dispersing unit main body and configured tosupply a plurality of thin film forming materials to a midway of the gaspassage; a cooling part disposed on an outer circumferential side of thecarrier gas introduction hole in the dispersing unit main body andconfigured to cool an inside of the gas passage; a cooling memberinsertion hole formed across almost an entire length of the center rodalong an axial direction of the center rod; and a cooling memberdisposed in an inside of the cooling member insertion hole andconfigured to cool the center rod.

With that preferred embodiment, it is possible to efficiently cool acarrier gas including the carrier gas having the thin film formingmaterials dispersed therein, the thin film forming materials beingsupplied from the thin film forming material supply parts.

In another preferred embodiment, the cooling part and the cooling memberare disposed across from at least near the thin film forming materialsupply part to near a downstream end of the gas passage.

With that preferred embodiment, it is possible to efficiently cool thecarrier gas having the thin film forming materials dispersed therein,the thin film forming materials being supplied from the thin filmforming material supply parts.

A MOCVD vaporizer according to yet another preferred embodiment includesa vaporizing part provided adjacent to the vaporizer and configured tovaporize a carrier gas having a plurality of thin film forming materialsdispersed therein in the dispersing unit main body.

The MOCVD vaporizer can improve the effect of preventing the clogging ofthe material of a carrier gas efficiently cooled using the cooling partand the cooling member, contribute to prolonging the timing ofmaintenance and improving operating efficiency, and exert more uniformdispersing effect.

A center rod according to a preferred embodiment is a center rod for usein the vaporizer or the MOCVD vaporizer, wherein the center rod includesa plurality of guide grooves formed on an outer circumferential portionof the center rod, the plurality of guide grooves corresponding to thinfilm forming materials to be applied one to one.

The cooling member can be a Peltier element in a nearly cylindricalshape.

The cooling member can be a heat pipe having a heat absorption partdisposed in the cooling member insertion hole.

The cooling member can be a spiral or nearly U-shaped cold water pipe,to and from which cooling water is supplied and drained through a pump.

The cooling member can be removably inserted into the center rod.

A method for cooling and dispersing a carrier gas includes the steps of:introducing a carrier gas having a plurality of thin film formingmaterials dispersed therein into a gas passage formed between an innerwall of a carrier gas introduction hole formed in a dispersing unit mainbody and a center rod inserted into the carrier gas introduction hole;and carrying the carrier gas having the thin film forming materialsdispersed therein through the inside of the gas passage while coolingthe carrier gas having the thin film forming materials dispersed thereinusing a cooling part disposed in the dispersing unit main body and acooling member disposed in the center rod.

It is possible to introduce a carrier gas efficiently cooled using thecooling part and the cooling member.

Moreover, an alternate method for vaporizing a carrier gas includessteps of: introducing a carrier gas into a gas passage formed between aninner wall of a carrier gas introduction hole formed in a dispersingunit main body and a center rod inserted into the carrier gasintroduction hole; and introducing thin film forming materials from aplurality of places in a midway of the gas passage to disperse the thinfilm forming materials into the carrier gas, joining the carrier gashaving the thin film forming materials dispersed therein at a joiningpart where a center rod tip end disposed on a downstream end portion ofthe gas passage guides the thin film forming materials in a direction tocome close to each other, and then vaporizing the carrier gas, whereinthe carrier gas having the thin film forming materials dispersed thereinis guided to the joining part while cooling the carrier gas having thethin film forming materials dispersed therein using a cooling partdisposed in the dispersing unit main body and a cooling member disposedin the center rod, the thin film forming materials being introduced fromat least the plurality of places in the midway of the gas passage.

It is then possible to contribute to vaporizing a carrier gas with fewimpurities mixed.

Effect of the Invention

The vaporizer according to the present invention can efficiently cool acarrier gas, improve the effect of preventing a material from beingclogged near the outlet port of a gas passage, contribute to prolongingthe timing of maintenance and improving operating efficiency, and exertmore uniform dispersing effect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view depicting the essential part of anembodiment of a MOCVD vaporizer according to the present invention;

FIG. 2A is a vertical cross sectional view depicting a center rod 35applied to the MOCVD vaporizer according to the present invention, andFIG. 2B is a cross sectional view depicting the center rod 35 applied tothe MOCVD vaporizer according to the present invention;

FIG. 3 is a vertical cross sectional view depicting a center rod 35 ofan exemplary modification 1 applied to the MOCVD vaporizer according tothe present invention;

FIG. 4 is a vertical cross sectional view depicting a center rod 35 ofan exemplary modification 2 applied to the MOCVD vaporizer according tothe present invention;

FIG. 5 is a cross sectional view depicting the essential part of aconventional vaporizer;

FIG. 6 is a cross sectional view depicting the essential part of anotherconventional vaporizer; and

FIG. 7 is a system block diagram depicting a MOCVD vaporization system.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

-   -   1 Vaporizer    -   2 Disperser (dispersing unit main body)    -   3 Reaction pipe    -   4 Heater    -   5 Gas passage        -   5 a Start upstream port        -   5 b End jet port (joining part)    -   6 Cooling passage    -   7 Center rod    -   8 Pin    -   9 Pin    -   10 Supply unit    -   11 Gas cylinder    -   12 Oxygen cylinder    -   13 Water storage tank    -   14 Reserve tank    -   15 Reserve tank    -   16 Reserve tank    -   17 Reserve tank    -   18 Gas supply pipe        -   18 b Mass flow controller        -   18 b Mass flow controller    -   19 Oxygen supply pipe        -   19 a Valve        -   19 b Mass flow controller        -   19 c Valve    -   20 Water supply pipe        -   20 a Valve    -   21 Distributing pipe    -   22 Liquid supply pipe        -   22 a Valve        -   22 b Mass flow controller        -   22 c Valve    -   23 Liquid supply pipe        -   23 a Valve        -   23 b Mass flow controller        -   23 c Valve    -   24 Liquid supply pipe        -   24 a Valve        -   24 b Mass flow controller        -   24 c Valve    -   25 Liquid supply pipe        -   25 a Valve        -   25 b Mass flow controller        -   25 c Valve    -   26 Manifold        -   26 a Valve        -   26 b Valve        -   26 c Valve        -   26 d Valve        -   26 e Air purge        -   26 f Valve    -   27 Thin film forming material supply part    -   28 Thin film forming material supply part    -   29 Thin film forming material supply part    -   30 Thin film forming material supply part    -   31 Connecting part    -   32 Connecting part    -   33 Cooling system    -   35 Center rod        -   35 a Cooling member insertion hole        -   35 b Guide groove    -   36 Cooling member    -   37 Anti-radiation part    -   38 Sealing member    -   39 Sealing member

MODE FOR CARRYING OUT THE INVENTION

Next, a MOCVD vaporizer according to the present invention will bedescribed with reference to the drawings. It is noted that since theappearance of the system configuration of a raw material supply systemor the like is the same as that shown in FIG. 7 in the followingembodiments, the detailed description of the overall system is omitted.

FIG. 1 is a cross sectional view depicting the essential part of anembodiment of a MOCVD vaporizer according to the present invention, FIG.2A is an enlarged vertical cross sectional view depicting a center rod,and FIG. 2B is an enlarged cross sectional view depicting the centerrod.

In FIG. 1, a vaporizer 1 includes a center rod 35 inserted into acarrier gas introduction hole formed in a disperser (a dispersing unitmain body) 2 to form a gas passage 5 in cooperation with the inner wallof the carrier gas introduction hole, a cooling path 6 disposed on theouter circumferential side of the carrier gas introduction hole in thedisperser 2 to cool the inside of the gas passage 5, a cooling memberinsertion hole 35 a formed across almost the entire length of the centerrod 35 along the axial direction of the center rod 35, and a coolingmember 36 disposed in the inside of the cooling member insertion hole 35a to cool the center rod 35.

Moreover, the disperser 2 is provided with thin film forming materialsupply parts 27 to 30 formed at a plurality of places in the disperser 2to supply a plurality of thin film forming materials to the midway ofthe gas passage 5 (only the thin film forming material supply parts 28and 29 are shown as faced to each other in FIG. 1).

At this time, the cooling path 6 and the cooling member 36 are disposedacross from at least near the thin film forming material supply parts 27to 30 to near the downstream end of the gas passage 5.

Furthermore, a vaporizing part that vaporizes a carrier gas having aplurality of thin film forming materials dispersed therein at thedisperser 2 is constituted of a reaction pipe 3 and a heater 4.

In the following, the specific configuration of the present inventionwill be described.

The vaporizer 1 according to the present invention includes the gaspassage 5 formed in the inside of the disperser 2 constituting thedispersing unit, a gas inlet port 18 a formed on a gas supply pipe 18 soas to communicate with the gas passage 5 for introducing a carrier gas,the thin film forming material supply parts 27 to 30 that supply rawmaterial solutions to the carrier gas passing through the gas passage 5for making the raw material solutions into mist, an end jet port 5 bthat supplies the carrier gas containing the raw material solutions inmist to the vaporizing part, the cooling path 6 for a cooling partthrough which cooling water is circulated for cooling the carrier gascarried through the inside of the gas passage 5, the reaction pipe 3having one end connected to the reaction pipe of a MOCVD device and theother end connected to the end jet port 5 b of the disperser 2, and theheater 4 that heats the reaction pipe 3.

The inside of the disperser 2 has a cylindrical hollow, and the centerrod 35 is inserted into the hollow carrier gas introduction hole. Theinner wall of the disperser 2 and the center rod 35 form the gas passage5. It is noted that the carrier gas introduction hole is not limited toa cylindrical shape, which may have other shapes. For example, a coneshape is preferable. Preferably, the conic angle of a cone-shapedcarrier gas introduction hole ranges from angles of 0 to 45°, morepreferably, angles of 8 to 20°. These are the same in the otherembodiments.

It is noted that preferably, the cross sectional area of the gas passageranges from 0.10 to 0.5 mm². Processing is difficult if the crosssectional area is blow 0.10 mm². A necessity arises to use a highpressure carrier gas at a large flow rate in order to increase the rateof a carrier gas if the cross sectional area exceeds 0.5 mm².

If a carrier gas at a large flow rate is used, a large-sized vacuum pumpwith a large capacity is necessary to maintain a reaction chamber at asubatmospheric pressure (1.0 Torr, for example). Since it is difficultto adopt a vacuum pump having an evacuation capacity of 10,000liter/min. (at, 1.0 Torr), an appropriate flow rate, that is, the gaspassage area ranging from 0.10 to 0.5 mm², is preferable, in order toachieve industrially practical use.

The gas inlet port 18 a is provided on one end of the gas passage 5. Agas cylinder 11 for a carrier gas (at least any one of N₂, Ar, and He,for example) is connected to the gas inlet port 18 a.

The thin film forming material supply parts 27 to 30 are provided inalmost the center part of the disperser 2 so as to communicate with thegas passage 5, in which raw material solutions are dropped andintroduced into the gas passage 5 and the raw material solutions aredispersed in the carrier gas passing through the gas passage 5, so thatthe raw material solutions can be made into a raw material gas.

An anti-radiation part 37 is provided at one end of the gas passage 5,in which the end jet port 5 b communicating with the reaction pipe 3 isformed.

The disperser 2 is formed with the cooling path 6 that circulatescooling water. The cooling water is carried through the cooling path 6,so that the carrier gas carried through the inside of the gas passage 5is cooled. It is noted that a Peltier element or the like may beprovided for cooling, instead of the cooling path 6. In addition, sincethe inside of the gas passage 5 is subject to heat caused by the heater4, only a solvent is vaporized without vaporizing the solvent andorganometallic complexes in the raw material solutions at the same timein the inside of the gas passage 5. Therefore, preferably, thevaporization of only the solvent is prevented by cooling the carrier gascarried through the inside of the gas passage 5, the carrier gas havingthe raw material solutions dispersed therein. At this time, since it isparticularly important to cool the downstream side of the gas passage 5more than the thin film forming material supply parts 27 to 30, it ispreferable to cool the inside of the gas passage 5 on the downstreamside more than at least the thin film forming material supply parts 27to 30. It is noted that the cooling temperature is a temperature of theboiling point of a solvent or less (a temperature of 67° C. or less forTHF, for example). More particularly, the temperature at the end jetport 5 b is important.

Thus, as shown in FIGS. 2A and 2B, the cooling member insertion hole 35a is formed on the axis of the center rod 35 according to the presentinvention, and the cooling member 36 that directly cools the inside ofthe center rod 35 is disposed in the cooling member insertion hole 35 a.It is noted that the outer circumferential portion of the center rod 35is formed with a plurality of guide grooves 35 b that efficiently supplythin film forming materials to be applied to the downstream side andcorrespond to the thin film forming material supply parts 27 to 30 oneto one.

It is noted that the center rod 35 is tapered so as to close to eachother in the axial direction from the midway to the start upstream port5 a side as shown in FIG. 2A.

At this time, preferably, the end portion is formed in a cone (or atruncated cone). The carrier gas introduction hole in the disperser 2 isformed so as to follow the shape of this tip end portion, so that thegas passage 5 is joined at the end jet port 5 b (a joining part). It isnoted that the end portion 37 a may be formed in a pyramid (or atruncated pyramid). At this time, for the number of corners (the numberof faces), a quadrangular pyramid is adopted as corresponding to fourthin film forming material supply parts 27 to 30. However, a polygonalpyramid can be adopted in which the number of faces corresponds to thenumber of the gas passages 5, that is, the number of raw materialsolutions (thin film forming raw materials) corresponding to the numberof the reserve tanks 14 to 17. It is noted that the guide groove 35 b isof course formed in each face in this case. In addition, although theend jet port 5 b is made at the joining part, the joining part may beprovided on the upstream side in the direction of carrying the carriergas more than the end jet port 5 b.

For the cooling member 36, one in a cylindrical shape, for example, isused in which the outer side is a heat absorption side and the innerside is the heat dissipation side. It is noted that 36 a and 36 b denotewiring codes of the cooling member 36 in FIG. 2B.

It is noted that the cooling member 36 is not limited particularly, suchas a heat pipe that the heat absorption side is positioned on the insideof the cooling member insertion hole 35 a and the heat dissipation sidepositioned on the outside of the cooling member insertion hole 35 a asshown in FIG. 3, for example, and a spiral (or nearly U-shaped) coldwater pipe that circulates cooling water as shown in FIG. 4. However,preferably, the cooling member 36 has a shape (thickness or the like)according to cooling temperature. Moreover, the cooling member 36 is notformed in a cooling passage or the like directly formed in the centerrod 35, so that it is possible to contribute to facilitating theformation of the center rod 35 and to facilitating maintenance such asdisassemble. Furthermore, the cooling member 36 is disposed acrossalmost the entire length of the center rod 35 to cool a carrier gasbeforehand. However, such a configuration may be possible that thecooling member 36 cools the inside of the gas passage 5 on thedownstream side more than at least the thin film forming material supplyparts 27 to 30 if the cooling temperature of the cooling member 36 canbe surely made higher.

Sealing members 38 and 39 such as an O-ring surely provide sealingproperties for the anti-radiation part 37 having the end jet port 5 bformed thereon. It is noted that preferably, the anti-radiation part 37is formed using a material having an excellent thermal conductivity suchas Teflon (registered trademark), stainless steel, or ceramics, forexample.

According to the findings of the present inventors, in the configurationin which only the outside of the gas passage 5 is cooled as described inthe conventional techniques, the heat in the vaporizing part overheats agas in the inside of the gas passage 5 as radiant heat through the endjetport 5 b. Therefore, even though the outside of the gas passage 5 iscooled with cooling water, a low melting point component in the carriergas is precipitated near the end jet port 5 b.

Thus, the aforementioned cooling member 36 is disposed and theanti-radiation part 37 is further disposed, so that it is possible tofurther suppress the propagation of such radiant heat to a carrier gas.Therefore, preferably, the cross sectional area of the end jet port 5 bis made smaller than the cross sectional area of the gas passage 5 (forexample, ½ or less, more preferably, ⅓ or less). Moreover, preferably,the end jet port 5 b is downsized. More particularly, preferably, theend jet port 5 b is downsized in the dimensions in which the flow rateof an issuing gas is subsonic speed.

Furthermore, preferably, the length of the end jet port 5 b is fivetimes the cross sectional dimensions of the end jet port 5 b or more,more preferably, ten times or more.

In addition, the disperser 2 is cooled to suppress the occurrence ofblocking caused by carbides in the inside of the gas passage 5(particularly the end jet port 5 b) for a long-term use.

The reaction pipe 3 is connected on the downstream side of the disperser2. The disperser 2 and the reaction pipe 3 can be connected using ajoint or the like.

In the foregoing configuration, a carrier gas is introduced into the gaspassage 5 formed between the inner wall of the carrier gas introductionhole formed in the disperser 2 and the center rod 35 inserted into thecarrier gas introduction hole. Thin film forming materials areintroduced from a plurality of places in the midway of the gas passage5, and the thin film forming materials are dispersed into a carrier gas.After at least the carrier gas having the thin film forming materialsdispersed therein is guided to the joining part while cooling thecarrier gas having the thin film forming materials dispersed thereinusing the cooling path 6 disposed in the disperser 2 and the coolingmember 36 disposed in the center rod 35, the thin film forming materialsbeing introduced from the plurality of places in the midway of the gaspassage 5. The carrier gas having the thin film forming materialsdispersed therein is joined at the joining part where the tip end of thecenter rod 35 disposed on the downstream end portion of the gas passage5 guides the thin film forming materials in the direction to come closeto each other. The carrier gas is heated and vaporized by the heater 4,and then the carrier gas is supplied to the thin film deposition device,not shown in the drawing.

INDUSTRIAL APPLICABILITY

As described above, according to the present invention, it is possibleto provide a vaporizer that can efficiently cool a carrier gas, improvethe effect of preventing a material from being clogged near the outletport of a gas passage, contribute to prolonging the timing ofmaintenance and improving operating efficiency, and exert more uniformdispersing effect.

1. A center rod constructed and arranged for use in a vaporizer, thevaporizer comprising: a center rod inserted into a carrier gasintroduction hole formed in a dispersing unit main body to form a gaspassage in cooperation with an inner wall of the carrier gasintroduction hole; a cooling part disposed on an outer circumferentialside of the carrier gas introduction hole in the dispersing unit mainbody and configured to cool an inside of the gas passage; a coolingmember insertion hole formed across almost an entire length of thecenter rod along an axial direction of the center rod; and a coolingmember disposed in an inside of the cooling member insertion hole andconfigured to cool the center rod; wherein the center rod includes aplurality of guide grooves formed on an outer circumferential portion ofthe center rod, the plurality of guide grooves corresponding to thinfilm forming materials to be applied one to one.
 2. The center rodaccording to claim 1, wherein the cooling member is a Peltier element ina nearly cylindrical shape.
 3. The center rod according to claim 1,wherein the cooling member is a heat pipe having a heat absorption partdisposed in the cooling member insertion hole.
 4. The center rodaccording to claim 1, wherein the cooling member is a spiral or nearlyU-shaped cold water pipe, to and from which cooling water is suppliedand drained through a pump.
 5. The center rod according to claim 1,wherein the cooling member is removably inserted into the center rod. 6.A center rod constructed and arranged for use in a vaporizer, thevaporizer comprising: a center rod inserted across an entire length of acarrier gas introduction hole formed in a dispersing unit main body toform a gas passage in cooperation with an inner wall of the carrier gasintroduction hole; a thin film forming material supply part formed at aplurality of places in the dispersing unit main body and configured tosupply a plurality of thin film forming materials to a midway of the gaspassage; a cooling part disposed on an outer circumferential side of thecarrier gas introduction hole in the dispersing unit main body andconfigured to cool an inside of the gas passage; a cooling memberinsertion hole formed across almost an entire length of the center rodalong an axial direction of the center rod; and a cooling memberdisposed in an inside of the cooling member insertion hole andconfigured to cool the center rod; wherein the center rod includes aplurality of guide grooves formed on an outer circumferential portion ofthe center rod, the plurality of guide grooves corresponding to thinfilm forming materials to be applied one to one.
 7. The center rod ofclaim 6, further comprising a plurality of guide grooves formed on anouter circumferential portion of the center rod, the plurality of guidegrooves corresponding to thin film forming materials to be applied oneto one.
 8. The center rod of claim 1, wherein the vaporizer is an MOCVDvaporizer comprising a vaporizing part provided adjacent to thevaporizer and configured to vaporize a carrier gas having a plurality ofthin film forming materials dispersed therein in the dispersing unitmain body, wherein the center rod comprises a plurality of guide groovesformed on an outer circumferential portion of the center rod, theplurality of guide grooves corresponding to thin film forming materialsto be applied one to one.
 9. The center rod according to claim 2,wherein the cooling member is removably inserted into the center rod.10. The center rod according to claim 3, wherein the cooling member isremovably inserted into the center rod.
 11. The center rod according toclaim 4, wherein the cooling member is removably inserted into thecenter rod.